src: raise the maximum open files limit on Windows#63643
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Pull request overview
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This PR increases the Windows CRT stream I/O limit during platform initialization (unless kNoAdjustResourceLimits is set) to reduce “too many open files” (EMFILE) failures in file-heavy workloads.
Changes:
- Add Windows-specific initialization that calls
_setmaxstdioto raise the CRT max open streams limit (up to 8192), with a fallback loop.
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On Windows, libuv uses the CRT's _open_osfhandle when opening files. This is constrained by the CRT's maxstdio limit, which defaults to 512, often causing "EMFILE: too many open files" errors for heavy workloads. This commit raises this limit on Windows up to the CRT maximum (8192) by invoking _setmaxstdio during PlatformInit, mirroring the POSIX behavior. Fixes: nodejs#44832 Signed-off-by: 郑苏波 (Super Zheng) <superzheng@tencent.com>
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Can we add a test? |
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #63643 +/- ##
==========================================
+ Coverage 90.28% 90.29% +0.01%
==========================================
Files 730 730
Lines 234802 234802
Branches 43953 43953
==========================================
+ Hits 211991 212023 +32
+ Misses 14530 14498 -32
Partials 8281 8281
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addaleax
approved these changes
May 29, 2026
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On Windows, libuv uses the CRT's
_open_osfhandlewhen opening files. This is constrained by the CRT'smaxstdiolimit, which defaults to 512, often causing "EMFILE: too many open files" errors for heavy workloads (such as modular building via webpack).This PR raises this limit on Windows up to the CRT maximum (8192) by invoking
_setmaxstdioduringPlatformInit, mirroring the behavior on POSIX platforms.Fixes: #44832